Generally in a machine, such as a wheel loader and the like, utilizing an implement based hydraulic system, it is desired to have the engine operating at a high engine speed to ensure proper operation of the hydraulic implement. Often this high engine speed, while desirable for operation of the hydraulic implement, provides too much torque to the drive train of the machine, wherein this torque can cause wheel slippage and increased tire wear.
When using the machine to push or move a pile of material with an implement, to prevent tire slip, the machine operator must lift or push into the pile to generate downforce on the tires. An inexperienced operator may lift too early, causing the implement to ride up and over the material, or lift too late, causing the tires to slip and wear prematurely.
One method to prevent wheel slip and tire wear is by controlling the rimpull of the machine though an adjustment of available torque to the drive train. Rimpull is generally defined as the force available at the wheels to move a wheeled machine forward. Traditional methods of controlling the rimpull are generally selected by or utilized by an operator of the machine prior to using the implement for lifting and moving. This type of system based upon operator selection prior to doing work has inherent drawbacks. A machine system is desired for adjusting machine rimpull proactively and on demand based upon machine operating parameters.